Hand-held device for measuring an analyte concentration in a sample of a body liquid

ABSTRACT

A hand-held device for measuring an analyte concentration in a sample of a body liquid includes a display means for displaying measured values; a measured-value storage for storing measured values; a measuring unit for generating measured values through measurements of the analyte concentration; a clock; a control unit for generating measured value datasets, each containing a measured value supplied by the measuring unit as well as the date and hour of the measurement by which the measured value was obtained, and for writing them into the measured-value storage; and operating elements that can be actuated by the user to set the clock, in which case the control unit will generate a time-correction dataset indicating the amount and direction of the setting effected. The control unit writes time-correction datasets into the measured-value storage so that a chronologically ordered sequence is generated containing time-correction datasets and measured value datasets.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/EP2009/008048 filed Nov. 12, 2009, which claims priority to EPApplication No. 08020879.6 filed Dec. 2, 2008. Each of the referencedapplications is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a hand-held device for measuring ananalyte concentration in a sample of a body liquid.

BACKGROUND

A hand-held device for measuring an analyte concentration has been knownfrom WO 2007/030457 A1 and is used for quantitative analysis of bodyliquids, for example of urine, blood and interstitial liquid, i.e. formeasuring the concentration of medically significant analytes such aslactate, cholesterol and, especially, glucose.

Hand-held devices of that kind can be carried along by the users and areneeded, for example, by diabetics who are required to measure theirglucose concentration on a sample of blood and/or interstitial liquidseveral times a day.

The measured values so obtained can be stored in a measured-valuestorage of the hand-held device for being transferred later to anexternal evaluation unit, for example a physician's PC. By evaluatingthe measured values obtained over an extended period of time it ispossible to optimize the medical treatment of chronic diseases such asdiabetes. Modern hand-held devices therefore comprise a clock so thatwhen the measuring results are evaluated later the development over timeof the analyte concentration can be examined in relation to a storedtime information.

The time-dependent relation between the different measured values may bedistorted when the setting of the clock is altered. This can be avoidedwhen the hand-held device is equipped with an internal clock that cannotbe set by the user, a system that has been known from DE 197 33 445 A1.Given the fact that medically relevant analyte concentrations normallyare subject to variation according to the rhythm of the day it is,however, desirable to provide the clock of a hand-held device with asetting function so as to allow the time of the day to be adjustedbetween summer time and winter time or on travels between different timezones. In order to ensure that the evaluation of measured valuesobtained over an extended period of time will not be distorted, it isnecessary that such time adjustments be recorded.

WO 2007/030457 discloses a hand-held device where measured values, aswell as the date and hour of the measurement by which the respectivevalue was obtained, are combined to form measured-value datasets whichare continuously stored in a measured-value storage. When the clock isset, the amount and direction of the change is stored in a storage(buffer log) provided for that purpose so that the respectiveinformation can be taken into account in evaluating the measured valueslater.

SUMMARY

The present invention shows a way how a sequence of measured values of ahand-held devise can be evaluated with little input and without beingfalsified by alterations of the time setting that may have been made.

The invention includes a hand-held device for measuring an analyteconcentration in a sample of a body liquid comprising: a display meansfor displaying measured values; a measured-value storage for storingmeasured values; a measuring unit for generating measured values throughmeasurements of the analyte concentration in samples of a body liquid; aclock for supplying the date and hour of the day; a control unit forgenerating measured value datasets, each containing a measured valuesupplied by the measuring unit as well as the date and hour of themeasurement by which the measured value was obtained, and for writingthem into the measured-value storage; operating elements that can beactuated by the user to set the clock, in which case the control unitwill generate a time-correction dataset indicating the amount anddirection of the setting effected, wherein the control unit writestime-correction datasets into the measured-value storage so that achronologically ordered sequence is generated containing time-correctiondatasets and measured value datasets.

Every time the clock is set, the hand-held device generates atime-correction dataset that indicates the amount and direction of thesetting and is stored in the measured-value storage of the hand-helddevice together with measured value datasets containing each a measuredvalue as well as the information on the date and hour the dataset wasgenerated. Accordingly, a chronological sequence made up from thetime-correction datasets and the measured-value datasets is generated inthe measured-value storage of a hand-held device according to theinvention. The time-correction datasets and the measured-value datasetare therefore sorted in the measured-value storage according to the timeof generation of the respective dataset. This provides severaladvantages:

-   -   A single storage suffices for a hand-held device according to        the invention. Thus it possible to save components and related        production costs.    -   The clock of a hand-held device according to the invention can        be set almost as often as desired, the number of time-correction        datasets that can be stored between measured-value datasets of a        series of measured values being limited only by the size of the        measured-value storage.    -   The position of a time-correction dataset within a series of        measured value datasets defines unambiguously the measured-value        dataset to which the respective time-correction dataset relates.        The exact time, i.e. the date and hour, of a setting effected        will not be required later for evaluation and, accordingly, does        not need to be recorded or stored so that the time-correction        datasets of a hand-held device according to the invention can be        given a very simple structure. The storage position of the        time-correction dataset within the measured-value storage,        together with the amount and direction by which the clock was        adjusted, are sufficient to permit correct evaluation of a        series of measured-value datasets.    -   Given the fact that time and time-correction information do not        have to be evaluated in the hand-held device, a hand-held device        according to the invention can be equipped with a very simple        and, therefore, cost-effective control unit. A series of        datasets in chronological order can be retrieved by an external        device from the measured-value storage of the hand-held device        without any difficulty via a hardware interface, and can be        evaluated at any time, all relevant information being contained        in the chronologically sorted sequence of datasets.    -   The evaluation can be restricted to any desired fraction of the        chronologically sorted sequence of measured-value datasets and        time-correction datasets. For, the time-dependent relation        between a desired number of successive measured value datasets        is clearly documented by time-correction datasets placed between        them so that any desired partial series of datasets can be        correctly evaluated without any additional information being        needed. This facilitates the use at a later time and the        repeated evaluation of data, that were obtained by a hand-held        device according to the invention, by an external device, for        example a physician's PC.    -   In the event of a partial loss of data the remaining part of the        data do not become worthless as the evaluation can be limited to        any desired number of successive data set.

An advantageous further development provides that the measured valuedatasets and the time-correction datasets have the same length. Thishelps simplify the architecture and management of the measured-valuestorage as all strings to be stored as datasets in the measured-valuestorage have the same length.

Time-correction datasets and measured value datasets can bedistinguished for example by a special data field or a flag. In oneembodiment, the time-correction datasets are identified as such by amarking that begins, related to the beginning of the dataset, in thesame position in which a field containing the measured value begins in ameasured value dataset. It is possible in this way to give the datasetsan advantageously short length as no additional field is required fordifferentiation. This is so because the marking envisaged by theinvention may, for example, include a string of characters or bitswhich, in a measured-value field of a measured value dataset, wouldrepresent a value that would be impossible physiologically. According toone embodiment, the marking may include a character string that beginsby the digit 9, especially by 99.

Having the marking begin with a string representing the digit 9 makes itpossible, for example, to use the bit string 99 or 999 as a marking fora time-correction dataset in a data field which, in a measured valuedataset, would contain a measured value, as corresponding concentrationvalues will never be encountered in practice.

It is further contemplated to give the markings of the time-correctiondatasets the same length as the field of the measured value datasetsthat contains the measured value. Even though two digits 9, followed byany third digit, would be sufficient in the described example as amarking for a time-correction dataset, a greater number of characters ordigits would provide improved safety from writing or reading errors.

In addition, the marking identifying time-correction datasets as suchcan be positioned at the beginning of a time-correction dataset. Thispermits time-correction datasets to be recognized as such.

BRIEF DESCRIPTION OF THE FIGURES

Further details and advantages of the invention will be describedhereafter with reference to one embodiment and to the attached drawings.In the drawings:

FIG. 1 shows an embodiment of a hand-held device according to theinvention; and

FIG. 2 shows the data structure of the datasets generated by thehandheld device.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended. Any such alterations and furthermodifications in the illustrated devices, and such further applicationsof the principles of the invention as illustrated herein arecontemplated as would normally occur to one skilled in the art to whichthe invention relates.

FIG. 1 shows an embodiment of a medical hand-held device 1 fordetermination of an analyte concentration in a sample of a body liquidof a person or an animal. In the illustrated embodiment, the hand-helddevice 1 is a glucometer, intended to be used by diabetics fordetermination of the glucose concentration in a sample of blood orinterstitial fluid.

For measuring, a sample of a body liquid is applied onto a test fieldsection of a carrier strip 2, and following a transport step of thestrip of suitable length the analyte concentration in the sample soapplied is measured in the device 1 by a measuring unit, for examplephotometrically or electrochemically. There is also the possibility toconfigure the hand-held device 1 in such a way that a concentration canbe determined with the aid of a consumable material in the form of teststrips. Test elements may be stored for example in a magazine in thedevice, or can be introduced together with the sample applied through anopening in the housing. For loading fresh consumable material, forexample a cassette containing carrier strip 2, or for replacingbatteries in a battery compartment, a housing part 6 is made detachable.

Measuring results of the analyte concentration are displayed by adisplay means 3, preferably a liquid crystal display, for example asegment display. The measured values so obtained may be displayedtogether with an indication of the date and hour, which may be suppliedby a clock integrated in the hand-held device 1. A control unit of thehand-held device 1, such as a microprocessor, generates from a measuredvalue and from the date and hour of the respective measurement ameasured value dataset and writes it into the measured-value storagewhich can be read out by an external device via a hardware interface 5.

In the illustrated embodiment, the hardware interface is designed forplug-in connection. There is, however, also the possibility to designthe hardware interface for wireless data transmission.

Operating elements 4 that can be actuated by the user are provided foroperation of the device 1 and, especially, for setting the clock. Whenthe integrated clock is set, the control unit of the device 1 generatesa time-correction dataset, defining the amount and direction of thesetting, and writes that dataset into the measured-value storage so thata chronologically ordered sequence of time-correction datasets andmeasured value datasets is generated in the measured-value storage. Thechronological order relates to the point in time at which the respectivedataset was generated and is derived automatically due to the fact thatthe datasets are stored in the measured-value storage simply one afterthe other.

FIG. 2 shows the structure of the datasets so stored in themeasured-value storage. The illustrated detail is a diagrammaticrepresentation of four successive datasets M1, T, M2 and M3,representing a section of a sequence stored in a measured-value storage.The datasets M1, M2 and M3 are measured value datasets, the record T isa time-correction dataset. The dataset M1, M2, M3 and T all have thesame length and contain four data fields A, B, C, D.

The first data field A has a length of four characters and contains, inthe case of the measured value datasets M1, M2, M3, a measured value ofa glucose concentration, for example in mg/dl. With respect to thetime-correction dataset T the data field D contains the entry 999 whichidentifies it as a time-correction dataset.

The second data field B also has the length of four characters andindicates, in the case of the measured value datasets M1, M2, M3, thehour of the day at which the measurement was taken, the first twocharacters identifying the hour, from 0 to 24, and the last twocharacters indicating the respective time in minutes, from 0 to 59. Inthe case of the time-correction dataset T, the data field B contains theamount by which the time was altered.

In the illustrated embodiment, the data field D of the time-correctiondataset T contains the number of minutes by which the time was adjustedso that in the case of a time-correction dataset the data field Bcontains an entry between 0 and the maximum number of minutes containedin 24 hours, i.e. 1140. In principle, it is however also possible toenter in the respective position of the data field of a time-correctiondataset the respective number of hours or minutes, in which case thefirst two digits of the data field B would indicate the number of hoursby which the clock was adjusted, while the two last digits of thedataset B would indicate the number of minutes by which the minute valueindicated by the clock was adjusted.

In the illustrated embodiment of the time-correction dataset T the clockof the hand-held device 1 was adjusted by 2 hours so that,correspondingly, the data field B shows the entry 0120 to indicate thatthe clock was adjusted by 120 minutes.

In the case of a measured value dataset the third data field C of thedatasets indicates the date when the measured values were obtained, thefirst two digits indicating the year, the next two digits indicating themonth, and the last two digits indicating the day in the illustratedembodiment. In the case of a time-correction dataset the last two digitsmay indicate the number of days by which the clock was adjusted, whilethe two digits before these last two digits indicate the number ofmonths, and the first two digits indicate the number of years by whichthe respective part of the date was adjusted.

The fourth field D of the datasets of the embodiment discussed abovecontains different flags that indicate if the entries in data fields Band C of a time-correction dataset are positive or negative, therebyindicating the direction in which the clock setting was altered. Forexample, the character B in the dataset T indicates as a flag that theclock was set back. Preferably, the field D additionally contains acheck bit or a check digit to allow a dataset to be checked for possiblewriting or reading errors. Additionally, the field D may contain anentry indicating whether the measured value of the respective measuredvalue dataset is above or below a predefined threshold value.

The data field B of a measured value dataset is described as a timefield in a measured value dataset and as a time-correction field in atime-correction dataset. Correspondingly, the data field C is describedas a date field in a measured value dataset and as a date-correctionfield in a time-correction dataset.

When the clock is set it may happen that the amount by which the clockwas adjusted cannot be determined. That case may arise for example whenthe device is started up for the first time or after an extended powerfailure, for example when the battery is replaced. In such a case, thecontrol unit will write into the storage a special dataset, preferablyof the same length and structure as the measured-value and thetime-correction datasets. Such a special dataset can be distinguishedfrom a time-correction dataset by a special marking that may bepositioned in the flag field D, for example.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatall changes and modifications that come within the spirit of theinvention are desired to be protected.

LIST OF REFERENCE NUMERALS

-   1 Hand-held device-   2 Carrier strip-   3 Display means-   4 Operating element-   5 Hardware interface-   M1, M2, M3 Measured value dataset-   T Time-correction dataset-   A, B, C, D Data field

1. Hand-held device for measuring an analyte concentration in a sampleof a body liquid comprising: a display means for displaying measuredvalues; a measured-value storage for storing measured values; ameasuring unit for generating measured values through measurements ofthe analyte concentration in samples of a body liquid; a clock forsupplying the date and hour of the day; a control unit for generatingmeasured value datasets, each containing a measured value supplied bythe measuring unit as well as the date and hour of the measurement bywhich the measured value was obtained, and for writing them into themeasured-value storage; operating elements that can be actuated by theuser to set the clock, in which case the control unit will generate atime-correction dataset indicating the amount and direction of thesetting effected, wherein the control unit writes time-correctiondatasets into the measured-value storage so that a chronologicallyordered sequence is generated containing time-correction datasets andmeasured value datasets.
 2. The hand-held device as defined in claim 1,wherein the measured value datasets and the time-correction datasetshave the same length.
 3. The hand-held device as defined in claim 1,wherein the time-correction datasets are identified as time-correctiondatasets by a marking that begins, related to the beginning of thedataset, in the same position in which a field containing the measuredvalue begins in a measured value dataset.
 4. The hand-held device asdefined in claim 3, wherein the marking of a time-correction dataset hasthe same length as the field of a measured value dataset that containsthe measured value.
 5. The hand-held device as defined in claim 3,wherein the marking begins by a bit string that represents the character9.
 6. The hand-held device as defined in claim 3, wherein the marking ispositioned at the beginning of a time-correction dataset.
 7. Thehand-held device as defined in claim 1, wherein the measured valuedatasets contain a time field that indicates the hour of the day whenthe measurement was taken, the time-correction datasets containing, atthe place where the time field is found in the measured value datasets,a time-correction field that indicates the number of minutes by whichthe hour of the day was changed by a clock setting operation.
 8. Thehand-held device as defined in claim 1, wherein the measured valuedatasets contain a date field that indicates the date on which themeasurement was taken, the time-correction datasets containing, at theplace where the date field is found in the measured value datasets, adate-correction field that indicates the number of days by which thedate was changed by a clock setting operation.
 9. The hand-held deviceas defined in claim 1, wherein the time-correction dataset contains aflag field that indicates the direction in which the setting was made.10. The hand-held device as defined in claim 9, wherein a flag in theflag field indicates the direction of the setting in minutes, while afurther flag indicates the direction of the setting in another timeunit.
 11. The hand-held device as defined in claim 10, wherein the timeunit of the flag that indicates the direction of the setting is in days.12. The hand-held device as defined in claim 1, wherein the control unitwrites a special dataset into the storage when at the time the clock isset no reference time is available that would be altered by the settingoperation and when, consequently, neither the amount nor the directionof a setting can be indicated.
 13. The handheld device as defined inclaim 12, wherein a special dataset can be distinguished from atime-correction dataset by a marking.
 14. The handheld device as definedin claim 13, wherein the marking by which a special dataset can bedistinguished from a time-correction dataset is positioned in the flagfield.
 15. The hand-held device as defined in claim 1, wherein thedevice is a glucometer.
 16. The hand-held device as defined in claim 1,wherein the device comprises a battery compartment.